Step 1

Heat oven to 325ºF.

Step 2

Mix flour, baking powder and zest in medium bowl. Beat butter and sugar in large bowl with mixer until blended. Add eggs and vanilla; mix well. Gradually beat in flour mixture until blended. Stir in nuts and chocolate.

Step 3

Place dough on lightly floured surface; divide in half. Roll each half into 14-inch log; place, 2 inches apart, on baking sheet sprayed with cooking spray.

Step 4

Bake 30 min. or until lightly browned. Transfer to cutting board; cool 10 min. Use serrated knife to diagonally cut each log into 18 slices, each about 3/4-inch thick. Place, cut-sides down, on baking sheets. Bake 25 to 30 min., turning over after 15 min. Remove to wire racks; cool completely.